A. Field of Invention
The invention of the present application relates to swimming pools having in-floor cleaning systems and, more particularly, to improved methods and apparatus for operating such pools with significantly less energy consumption and/or the use of fewer in-floor cleaning heads and related plumbing. The methods and apparatus of the present invention have utility in retrofitting existing swimming pools for greater energy efficiency and in the construction of new swimming pools that are more energy efficient and/or less costly to construct. The methods and combined structures of the present invention can be used to substantially increase the energy efficiency of a wide range of differently configured swimming pools that incorporate in-floor cleaning systems from several different manufacturers and various combinations of commercially available components.
B. Prior Art Systems, Components and Patents
1. Filtration and Skimming Systems—FIG. 1 shows the basic elements of a prior art swimming pool including: a concrete, vinyl or fiberglass pool 1 having an optional steps 2 and seating area 3 at one end; a main drain 4 and skimmer 5 through which water is drawn from the pool 1 through a strainer 6 by a pump 7 that circulates pressurized water through a filter 8 and through various fittings back into the pool 1. The pump 7 is driven by an electric motor 9 which is selectively activated by a 24-hour timer 10 that sets the length of time and the time of day that the motor 9 is connected to a source of electric power 11. A three-way valve 12 has two inlet ports that are in separate fluid communication with the skimmer 5 and the main drain 4. The valve 12 is used to selectively balance the flow of water drawn from the skimmer 5 and the main drain 4, through the strainer 6 and into the suction side of a pump 7. The individual components of prior art swimming pools such as the one shown in FIG. 1 can assume many different forms; for example: the filter 8 may be a sand, diatomaceous earth or paper cartridge filter; the skimmer 5 may be a suction type as indicated in FIG. 1 or a pressure/venturi type shown in FIGS. 2 and 6B. Likewise, the drain 4 may take the form of a single drain or a plurality of separate drains.
2. In-Floor Cleaning Systems—FIG. 1 also shows the additional elements used in prior art swimming pools having in-floor cleaning systems. Included are a multiport distribution valve 16, which in this example has six output ports numbered as such. The multi-port distribution valve 16 receives pressurized flow from the output of the pump 7 (after it passes through the filter 8) and directs this flow sequentially through the separate outlet ports identified in FIG. 1 as ports 1 through 6 on valve 16. Each of the outlet ports (1 through 6) on valve 16 is in separate fluid communication with one of the sets of individual popup cleaning heads 17. As shown by the broken lines connecting individual popup heads 17 in FIG. 1, these popup heads 17 are commonly plumbed in six sets. Each of these sets is in separate fluid communication with one of the six outlet ports on valve 16, as indicated by the broken flow arrows labeled Port 1 through Port 6. The individual popup heads 17 are flush mounted in the surfaces of the pool 1 and distributed over the surfaces of the pool to allow even cleaning.
3. Commercial Systems and Patents—The structure and operation of in-floor cleaning systems, including the rotating valves and popup heads they incorporate are well known and have been the focus of extensive research, development, commercial and patent activity over the past three decades. Examples of prior art rotating valves include: (a) the early rotating valve manufactured by Pinnacle Engineering and described in U.S. Pat. No. 3,779,269; (b) the rotating valves manufactured by Shasta Industries, Inc. and exemplified by U.S. Pat. Nos. 4,523,606, 4,570,663, 4,817,656, 6,189,556, 6,325,087, and 6,539,967; (c) the rotating valves manufactured by Paramount Leisure Industries, Inc and exemplified by U.S. Pat. Nos. 4,592,379, 6,311,728, 6,314,999 and 6,360,767; (d) the stepping motor valve manufactured by Polaris Pool Systems/Caretaker Systems Inc. as shown in U.S. Pat. No. 6,345,645; (e) the “Net'N'Clean” rotating valve sold by Astrol; and (f) the “Q360” rotating valve sold by Blue Squared Manufacturing. In general, all of these distribution valves can be either retrofitted to incorporate the cam of the present invention or replaced with a distribution valve that functions in accord with the present invention. Examples of prior art cleaning heads include: (a) the early cleaning heads marketed under the “Turbo Clean” brand as described in U.S. Pat. Nos. 3,408,006 and 4,300,246; (b) the popup heads manufactured by Shasta Industries, Inc. and exemplified by U.S. Pat. Nos. 4,322,860, 4,523,606, and 6,971,588; (c) the popup heads manufactured by Paramount Leisure Industries, Inc and exemplified by U.S. Pat. Nos. 3,521,304, 5,251,343, 6,301,723, 6,367,098, 6,393,629, 6,601,244, 6,848,124, and 7,578,010; (c) the popup heads manufactured by Polaris Pool Systems/Caretaker Systems Inc and exemplified by U.S. Pat. Nos. 4,271,541 and 4,371,994; (d) the “Net'N'Clean” head sold by Astrol; and (e) the “Q360” head sold by Blue Squared Manufacturing. In general, systems that incorporate these popup heads can be retrofitted to incorporate the methods and apparatus of the present invention. These and many other components and parts for in-floor cleaning systems are commercially distributed through Infloor Parts.Com (http://www.infloorpool parts.com/). The disclosures contained in the prior U.S. patents identified in this paragraph are incorporated herein by reference.
Factors Affecting Energy Consumption
1. Energy Consumption—In the context of single family homes, the most energy-intensive functions are those related to space heating and cooling. Where present, swimming pools consume the second largest amount electrical energy in homes. The amount of energy required for operation of a swimming pool is dictated primarily by the size and capacity of the pump motor plus the speed and length of time that the pump motor must operate for effective filtration and cleaning. The capacity of pump motors on any particular pool is dictated by many factors, including the volume of the pool, the distance from the pump to the pool and the flow demand of associated water distribution and utilization components, such as: pipes and connectors; skimmers and other debris removal elements; spas; and aesthetic features including water jets, fountains and waterfalls.
2. Energy Trends—The past thirty years have seen a substantial increase in the average size of swimming pools and a further increase in flow demand due to the incorporation of more water-driven features. These increases have required the use of higher capacity pumps and motors for effective operation. Pool pump motors in the 1970's were typically rated in the range between three-quarters and one horse power. Present day swimming pools typically have pumps capable of producing between one-and-a-half and three horse power. This increased demand for pumping capacity has come at the cost of proportionately increased energy consumption. Higher pumping capacity has also required larger diameter and more expensive plumbing components to accommodate the higher flow rates, thus increasing the initial cost of constructing swimming pools. In the 1970's swimming pools incorporated plumbing components characterized by an inside diameter of 1.5 inches; today flow capacity has been increased by over 175% (1.00/0.56×100%) requiring plumbing components based on a minimum of a 2 inch inside diameter and return/suction lines having inside diameters of 2.5 inches or greater.
3. Conservation Incentives—For many years, there have been state, federal and utility-sponsored programs that provide tax deductions, tax credits, utility rebates and other incentives to encourage home owners to install or replace existing electrical appliances with newer units having greater energy efficiency. Efforts to operate swimming pools using less energy have focused almost exclusively on the use of pump motors that are more efficient or capable of operating at variable speeds and the use of timers to limit the number of hours the pool pump operates each day.
4. Pump Run Time—Over the past decade, standard pump motors have been increasingly replaced by motors that cost more but produce the same output with approximately 20% greater efficiency. Inexpensive timers have been widely used to limit the pool motor operation to between 8 and 12 hours per day, depending on the volume of the pool and the rate at which the pump circulates pool water through the filter. Some pools also use timers to limit the pool motor operation to “off-peak” hours (typically between 9 p.m. and 6 a.m.) to take advantage of lower electrical rates charged by most utilities during times when system-wide usage is a fraction of the utility's peak generation capacity. These “time of day” controllers reduce the cost of electrical energy but they do not reduce the actual amount of energy required for proper operation of the swimming pool cleaning system. More recently, multiple speed and variable speed motors are replacing single-speed pump motors that operate at a fixed speed of 3450 revolutions per minute (rpm). Variable speed motors allow the pump to be operated at a high rpm when flow requirements are high and at a significantly lower rpm when a lower flow rate is sufficient for long-term functions such as water circulation and filtration. A properly designed variable speed motor will consume less electrical energy at lower speeds than at higher speeds; and, in many cases, the energy savings is disproportionately greater than the reduction in motor speed. For any particular swimming pool, a reduction in the pump run time will produce the greatest amount of energy savings, so long as the reduction in run time does not adversely impact the cleaning, filtration or disinfection functions required for safe and enjoyable long-term use of the pool.
5. Basic Turnover Time—For proper water filtration and treatment of any given swimming pool, it is generally required that a minimum volume of water be circulated through the filter during each 24-hour period. This minimum volume of circulated water in the case of residential pools is generally recognized as being equal to the volume of water in the pool itself. The time required to circulate this volume of water is referred to as the “turnover” time for the particular pool. For an average sized residential pool having a volume of approximately 20,000 gallons, the turnover time would be the time required for the pump to circulate 20,000 gallons through the filter. With a properly sized pump and motor, this turnover time has typically required operation of the pump for between 8 and 10 hours each day to assure adequate filtration and treatment of the water. The total amount of time required for adequate filtration can increase or decrease for any particular pool depending on how heavily it is used, the time of year and weather conditions that affect the cleaning load on the pool.
6. In-Floor Turnover Time—Swimming pools having in-floor cleaning systems have been increasingly adopted since they were introduced some thirty years ago. While adding to the initial cost of a pool, these systems have been justified by a significant reduction in the amount of time and labor required for regular pool cleaning. In addition, these cleaning systems do not detract from the critical aesthetics of a pool, since they eliminate unsightly mechanical whips or crawling devices. In-floor cleaning systems operate in response to a pressurized flow of water delivered to pop-up cleaning heads at a minimum operating pressure, which typically ranges between about 5 and 10 pounds per square inch, depending upon a number of design factors. The flow of water through these cleaning heads not only aids in the suspension of particles and transport of debris from the pool surfaces, this same flow counts toward the required daily “turnover” of the pool water for filtration purposes. In addition to their cleaning function and contribution toward daily turnover, popup heads serve to return filtered, treated and uniform temperature water to the pool at widely distributed points.
7. Cleaning Cycle—Pools having in-floor cleaning systems must be operated each day for a period of time that is a function of both the “turnover time” and the “cleaning time.” The cleaning time is, in turn, a function of the number of “cleaning cycles” required for the jet emitted from each popup head to properly transport dust and debris from within cleaning radius of that head. In-floor cleaning heads rotate on an incremental (or in some cases random) basis each time they are activated by the flow of pressurized water. For example, a popup head that rotates in increments of about 30 degrees each time it is activated will complete one “cleaning cycle” when it has been activated 12 times resulting in its jet being directed to the surrounding 360 degrees of surface area within its cleaning radius.
8. Cleaning Time—Depending on the flow rate through the rotating, multi-port distribution valve (16 in FIG. 1), the valve will complete one full rotation every few minutes. During one full rotation of the distribution valve, each of the six ports will direct the pressurized flow of water to one set of popup heads and each of the individual popup heads will be activated, will direct a jet of water along the adjacent surface of the pool and will then advance to the next incremental position. For example, in reference to FIG. 1, if the flow from the pump 7 to rotating distribution 16 is at a rate that drives the valve to complete one revolution in about six minutes, then each set of popup heads 17 will be activated and rotate incrementally once every six minutes. If a popup cleaning head increments 12 times for each 360 degree cleaning cycle, then each such cleaning cycle will take about 72 minutes. (6 minutes per valve revolution multiplied by 12 increments per head rotation equals 72 minutes per cleaning cycle). The “cleaning time” for a swimming pool having this configuration would depend on the number of cleaning cycles that must be completed for adequate movement of debris and particles from the surface of the pool toward and into the drain for transport to the filter. Total cleaning time for this type of system could range from four to eight cleaning cycles, depending on the configuration of the pool, location of the popup heads, volume of flow and the operating pressure delivered to the popup heads. Cleaning time can also be influenced by exterior conditions that cannot be planned for such as wind storms and particularly heavy use of the pool.
9. Dwell Time—The concept of “dwell time” as a measure of cleaning effectiveness and efficiency was introduced, explained and empirically documented in the application entitled “Improved Distribution Valve and Cam Mechanism” filed Jan. 29, 2010 and assigned Ser. No. 12/657,882, now U.S. Pat. No. 8,256,451, of which the present application is a continuation-in-part. “Dwell time” is the period during which a popup head is activated and receives a flow of water at or above a peak operating pressure. As described in the parent application (see FIGS. 9 through 13), the effective cleaning area associated with popup heads is significantly enhanced by configuring the cam used in rotating distribution valves: (a) to reduce or generally minimize the duration of concurrent flow through adjacent outlets of the distribution valve and (b) to increase or generally maximize the duration of flow to said popup heads at a pressure that equals or exceeds a predetermined minimum operating pressure associated with said popup heads (see FIGS. 9 through 13). This simple innovation in the design of distribution valves has been shown to substantially increase the functional dwell time without any modification to the popup heads, while increasing the effective cleaning area of the popup heads by a factor of between 30% and 75% compared to identical heads operated under identical conditions using the same distribution valve incorporating a prior art cam (see FIGS. 14 through 16 in the parent application).
10. Dwell Factor—An operating combination of popup heads together with a particular distribution valve can also be characterized in terms of a “dwell factor,” which measures not just the time that head pressure is above a peak value but accounts for the summation or integral of head pressures above a predetermined operating pressure over the entire dwell time. It is thought that the dwell factor is a more complete indicator of the relative cleaning efficiency of an in-floor system. As compared to an otherwise identical system using a prior art distribution valve, the same system using the present invention will produce a dwell factor that is between 60% and over 200% greater than the dwell factor associated with the prior art system.